Influence of zirconium addition on final properties of K0.5Na0.5NbO3-based ceramics

Microstructure, electrical and dielectric properties of K_1/2Na_1/2NbO₃ (KNN) modified with ZrO₂ were investigated. Powders were obtained by a conventional solid-state method. Samples doped with 0–2 mol% of ZrO₂ were sintered at 1,125 °C for 2 h. Through XRD spectra, the perovskite structure was observed, in addition to small peaks corresponding to secondary phases. It was also determined that zirconium drastically changed the microstructure and grain size of KNN ceramics. The addition of upto 1.0 mol% of Zr⁴⁺ produced a softening effect in the ferroelectric properties of the material, and increased its density. Conversely, samples prepared with contents higher than 1.0 mol% reduced piezoelectric and dielectric properties.